Arduino Finger Print Car starter


I came across this finger print scanner made by ada fruit I thought it would be a fun project to hook this up to the starter of my car. I know that this isn't an ensured security for my car but it would be a cool gimmick.

I was thinking I just need to interrupt the 12v power that is sent to the starter when the key is starting the car with a relay and have whichever pin I choose to be HIGH while the scanner is working to be the trigger for the relay.

So I basically need a 12v 60-80amp relay that can be triggered by 5v.

Please let me know if I have this all wrong and if you have a relay suggestion for my project. Thanks in advance and I apologize for the newbie question.


In the cars with which I am familiar, the starter solenoid (a relay in itself) does not require anything near 60 amps.

More likely less than five amps, but do not quote me on that. Various options include research on specifications, and trial and error with the 10 amp scale of a common $5 multimeter - but the risk is yours, not mine.

I suspect a readily available relay module will be just fine.

Hello Paul B

Thanks for the reply. You are correct I said the wrongnamps. Which relay module were you thinking of?

If you examine the details on the top of the relay, I think most of those advertised in modules on eBay.